Mechanical time fuse



Feb. 25, 1941. M, L MATHSEN ETAL 2,232,714

MECHANICAL TIME' FUSE Filed Oct. 1. 1937 3 Sheets-Sheet 2 Inventnrs Marvin L Maths En A? Chih a1 d E Renhar d VMM Attorney Feb 25, 1941-V M. l. MA-rHsEN am. 2,232,714

uEcmIcAL TIME. russ Filed Oct. 1, 1937 3 Sheets-Sheet 3 ITLVETLL DrE Marvin L Mathsen Ar :hhal E Renhard /oo y Attnrney Patented Feb. 25, 1.941A

mamon. 'rma Foss Marvin L. Mathsen, Wharton, and Archibald E.

Reinhard, Dover, N.'3., signora to the Government o! the United States of America, represented bytheSecretaryotWar Application October 1, 1937. Serial No. 166,772

19 Claims. (Cl. 102-36) (Granted under the act of March 3, 1883, as amended April 30, 1928: 370 0. G. 757) 'I'he invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

The subject of this invention is a mechanical time fuse.

The purpose of the invention is to provide a rugged and waterproof mechanical time fuse which will meet a large number of requirements relating to safety and to functioning. The fuse is so constructed that commencement of flight is necessary for partial arming and impact is lnecessary to permit starting of the clockwork move- 15 ment which must run for a period of approximately iive minutes before permitting a detonator to be moved into line with a iiring pin.

A further object of the invention is to provide a simple and eiiicient connection between the timing lever and a lever which restrains the nring pin whereby the ring pin spring exerts its inuence to hold the timing lever against a set-l ting disk. v

Other objects of the invention are to provide means, functioning at the commencement of flight for locking the cover of the fuse casing and for locking the fuse casing to the bomb body.

To these and other ends, `the invention consists in the construction, arrangement and combnation of elements descrlbed'hereinafter and pointed out in the claims forming a part of this specication.

A practical embodiment of the invention is il lustrated in the accompanying drawings, wherein: e Fig. 1 is n longitudinal sectional view, partly in elevation of the improvedv fuse, the section being taken on the line I--I of Fig. 5.

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 5.

`Fig. 3 is a sectional view on the line 3-3 of Fig. 2.

Fig. 4 is a sectional view on the line 4-4 of Fig. 3.

Fig. 5 is a plan view with the cover removed.

Figs. 6, 7 and 8 are sectional views on the corresponding lines of F18. 2.

Fig. 9 is a sectional view on the' line 9-3 of Fig. 5.

Fig. 10 is a plan view, with the cover removed, of a modiiied form of the invention.

Fig. 11 is a sectional view on the line II-II of Fig. 10.

Figs'. 12 and 13 are sectional views on the corresponding lines of Fig. 10. Y The fuse casing comprises an inner portion' I (Figs. 1 and 2) and an outer portion 6, the inner portion being inserted in and threaded attached to a bomb body 1, and the outer portion being considerably larger in diameter and closed by a removable cover 8 which is threaded in place and '5 contines a packing ring 9. The outer portion carries a pawi Io (Fig. 1) which is acted on by a spring II to hold it in engagement with the bomb and prevent removal of the casing from the bomb. An aperture l2 in the side wall of the 1 outer portion 5 provides for insertion of arod or similar 'article to move the pawl out of engagement with the bomb, but this can only be accomplished when the cover 8 is removed.

The casing houses a more or less conventional clockwork movement including a barrel I3 xed in place in the outer portion by screws I4 and enclosing a spiral main spring I5. The main spring drives a hollow spindle I8 which, through gearing l1 (Fig. 4) drives gearing la en e spindle 2 I9 passing through the hollow spindle I6. 'I'he usual regulating gear trains including escapement control are carried in a series of disks 20 which are disposed in the inner portion 5 of the casingv and are mounted on rods 2I seated in the barrel I3. The disks are confined between the barrel and a block 22 in which the rods are threaded. A setting disk 23 xed on the outer spindle I3 has a marginal scale 24 (Fig. 5) graduated ln nours' and a setting disk 2s nxed on 3 the inner spindle I9 has a marginal scale 26 graduatedinminu The block 22 is providedbn its inner side with a recess 21 which is conveniently formed by interposing a segment of a ring 23 between the 35- l block 22 and a thin disk 29, the ring and disk being secured to the block by means of screws 33 (Fig. 8). A firing pin 3| mounted in the block has a tapered shoulder 32 adjacent the point on its inner end. The ring pin is normally held in 40 the safe or retracted position against the iniiuence of a ring pin Vspring 33 by means of a pair of levers 34 and 35 which are disposed in the recess 21 and are mounted respectively on pivot pins 36 and 31 threaded in the block. 'I'he inner 45 ends of the levers are preferably beveled and adapted to engage the tapered shoulder 32 of the 'tiring pin. The point of the rlng pin is norber 4I between the diaphragm and a closure plate 43 is mounted on a pivot pin 43 and carries a detonator 44. The rotor is held in the unarmedposition with its detonator out of line with the 55 firing pin by means of the segmental inner end 45 of a starter control rod 46. When the segmental end is turned out of engagement with a nose 41 of the rotor, the rotor is free to be rotated by its spring 49 to position the detonator in line with the firing pin. As seen in Fig. 8 the inner end 45 of the rod is also engaged by the outer end of the lever 34 and serves to oppose movement of the lever.

The rod 46 passes through the block 22 and disks 28 and its outer end is formed into a head 49 (Fig. 2) which is normally disposed in the barrel I3 and supported by a shearable washer 56. The washer is held in place by a hollow plug 5I which encloses the head 49. l A segmental gear 52 (Figs. 3 and 4) is provided on the rod adjacent its head and is in mesh with an elongated pinion 53 which in turn is in mesh with the gearing I8. A pin 54 (Fig. 6) nxed transversely in the rod has projecting ends disposed in slots 55 in one of the disks 28 whereby the rod is held against rotation. For purposes of assembly each disk is formed with the slots 55. On impact the rod shears the washer 58 and moves longitudinally to remove the pin 54 from the slots. The rod is now free to be rotated by the clockwork movement, whose starting is controlled, and after predetermined interval, 41/2 minutes in the present example, the rod has been turned sufficiently to release the rotor 40 and the lever 84.

The rod 46 is additionally held against longitudinal movement by an arming mechanism which includes a plunger 56 (Figs. 2 and 4) mounted in a passage in the outer portion 6 of the casing and arranged perpendicular to the rod. 'Ihe inner end of the plunger is insertable in an aperture 51 in the rod while the intermediate portion of the plunger includes a collar 58 acted on by a spring 59 normally tending to withdraw the plunger from the rod. 'I'he collar has a, sharp outer edge 60 (Fig. 2) adapted to be forced into a washer 6| to establish a iluid seal when the plunger is moved by its spring. The outer portion ofthe plunger passes through a plug 62, supporting the washer 6|, and its extremity is engaged by a second plunger 63, perpendicular .to the ilrst plunger, and carried in a bracket 64 4attached to the fuse casing.

The plunger 63 is heldin position to oppose withdrawal of the plunger 56 from the starting rod by means of an arming bolt 65 (Fig. 2) mounted in a laterally projecting tube 66. The outer end of this tube is threaded to permit the addltionf of a similar tube and an increase in length to adapt it for bombs of larger sizes. The arming bolt is held by a cotter pin 61 when in storage but when the bomb is placed in the rack of aircraft, the ootter pin is removed and the arming bolt is held by the arming wire 68 which is withdrawn in the well known manner when the bomb is launched from the aircraft. The adjoining ends of the arming bolt 65 and the plunger 63 are.conica1 so that when the arming bolt has been freed by withdrawal of the arming wire it may be moved aside by the plunger 63 which is ejected from the fuse casing by its spring 69, thereby releasing the plunger 56.

A bolt 18 mounted in the fuse casing adjacent and parallel to the plunger 63, is normally held in retracted position. against the action of a spring` 11, by means of a ball 12. The ball is adapted to engage a shoulder 13, formed by reducing the bolt, and isheld in engagement therewith by the plunger 63. On removal of the plungerl 63, the bolt is moved by its spring and forces the ball to one side into a recess 14. When the -bolt is released its outer end engages the cover 6 where it enters one of an angular row o'f recesses 15 in the cover or is positioned betweenV the recess so that any attempt to unscrew the cover wlll'result in its engagement in one ofthe recesses.

A timing lever 16 (Figs. l, 5 and 9) fixed to a pivot pin 11 which is mounted in the barrel I3 carries an upstanding iinger 18 which is adapted to ride on the periphery of the setting disks 23 and 25 and to successively enter a wide-mouthed recess 19 in the disk 23 and a recess 80 in the disk 25. 'I'he timing lever is locked against movement by a pin 8i which is removed after the fuse has been set for time functioning. The pin 8i passes through a setting indicator 82 fixed to the barrel. then through the timing lever 16 and then into the barrel. The indicator 62 includes a pointer 83 readable against the hour scale 24 and apointer 84 readable against the minute scale 26.

The inner end of the pivot pin 11 which carries the timing lever hasa semi-circular segment 85 which is arranged to engage the free end of a lever 86. 'I'he pivot of the lever 86 consists of a long rod 81, quite similar to the starter control rod 46 and extending through the disks 28 and block 22, and terminates in a segment 88 (Fig. 8) which is disposed in the recess 21, and engages the outer end of the lever 35. 'I'he ring pin spring 33 acting through the firming pin tends to rotate the lever 35 and this influence is transmitted to the rod 81, the lever 86, and the pivot pin 11 and as a consequence the linger 18 of the timing lever 16 is held against the periphery of the setting disks and caused to move into the recess of the disks. Conversely, the firing pin cannot move so long as the nger 18 rides on the periphery-of the larger setting disk 23 and it is not fully released until the finger enters the recess in the smaller setting disk 25 at the expiration of the setting time.

The disks 23 and 25 are provided with aperturesfrespectively 89 and 90, for the application of a wrench, not shown, whereby the disk-may be manually set for a desired time of functioning which is indicated on the scales 24 and 26 by the pointers 83 and 84. In Fig. 5 the setting is for 50 minutes and 0 hours and as lsoon as the timing lever is released by removal of the pin 8|, the finger 18 movesl through the recess 18 in the hour disk 23 and engages the periphery of the minute disk 25. After the fuse has been thus set the cover 8 is applied to the casing and the bomb is ready to be launched.

When the bomb is launched, the arming wire 68 is automatically Withdrawn and the plunger 63 being no longer held by the arming bolt 65 is ejected from the casing.` 'Ihe bolt 10 is now released to engage the cover and the plunger 56 is withdrawn from the starter control rod 46. The fuse is now only partially armed. On impact, the starter rod is driven forwardly and its pin 54 removed from the slots 55. The starter rod which heretofore hady held the clockwork movement is` now rotated by said movement and at the lend of 41/2 minutes it has been turned sufciently to release the rotor 48 and the lever 34.

The clockwork movement drives the setting disks- 23 and 25 and upon the expiration of the time set for functioning the entrance of the recess 88 of the disk 25 will be in position to receive the nger 18I of the timing lever. It is to be remembered that the lever 16 preliminary to its Yio ' 4,asavia arming bcltl'- eii'fends in fthe-iusefcasing1l y and engagesarokel'carri'ed by afguide pin'lli'.' The yoke when-rengagedin opposes] movement ot: ,la of as and ss mountesinytne casing, f-oaefone, ofthe plunger 'Il when the plunger is [the hour setting 23, be dependent on lthe setting timi-ng'lever is'rotated as Vthe Il drives :the ming loto, me uetonator or .the -rotor in the mnnerrrevlouslvdwbed.,

In the modiiication Figa-10411115116 released, to engageand lock'jthe 'cover'l'l vwhile the other end normally controls oi a plunger 98 i'romthestal'ter oontrolrod Il. vThe plunger 98 (Fig. lil)Vv when restrained by the yoke engages a pawl |00. and serves to hold it out oi locking engagementxwlth thebomb. By virtue of this arrangement, the `fuse may be removed from the bomb and replaced by aiuse of a dii.'- ferent type at anytime prior tofactual launching of the bomb and lrelease ot the arming bolt.

'I'he time functioning mechanism 'includes a single setting disk IIII, graduated in `holn's, a.nd having a recess '|02 for reception of the `timing lever |03. Avspring-pressed plunger |04 mounted in the barrel has aproiectingnnger III which is adapted to engage thedisk Ill and be interposed in the path of movement of a lug |01 on the under side of the disk. The lug is so located that it will engage the linger and prevent rotation of the disk to a position which would allow the timing lever |03 to enter the recess |02. When the setting disk has been adjusted to the desired time of functioning by acting on the handle |08 the cover 91 is applied to the fuse casing and serves to displace the plunger |04 and remove the finger from the path of the lug. In this arrangement it is not necessary to employ the pin 8| of Fig. 9. .l

While the fuse -is shown as applied to a bomb it may be readily adapted to projectiles iired from a barrel.

1. In a fuse for bombs, a casing including a removable cover, a clockwork movement in the casing including a pair of'setting'disks each having a peripheral recess. a ring pin in the casing, a firing pin spring, -a pair of levers for holding the tiring pin in retracted position, a rotor having a detonator, a starter control rod engageable with untilv it has'been displaced longitudinally on impact. means releasable on launching of the bomb for holding the starter rod against rotational and longitudinal displacement, means associated with said preceding means for locking the cover to the casing, a timing lever adapted to ride on the periphery of the setting disks and to successively enter the recesses of said disks, a pivot pin for the timing lever'. having a segment, a rod having a segment on one end engageable with the other firing pin holding lever, and a lever on said rod engaging the segment of the pivot pin of the timing lever.

2. In a fuse for bombs. a casing including a removable cover, a clockwork movement in the casing including a timing lever having va segment, a iiring pin in the casing, a nring pin spring, a pair of lever's for holding the tiring pin in retracted position, a rotor having a detonator,

"a starter control rod-cngageable with the clock@ L -work movement, the inner end oithe rod including a segmentiior holding the rotor and one or the firing pin .holding levers. means whereby the starter rod is. held against rotation until it has been displaced longitudinally on impact.' means releasableon launching ot the bomb for holding the'starter rod against rotational and longitudinal displacement, means'associated with said preceding means for locking the cover to the casing, a rod having a segment on one end ensag'eable with the other Bring pin holding lever, and a lever on said rod engaging the segment of the timing lever.

3. In a iuse for bombs, a casing, a clockwork movement in the casing including a timing lever having a segment,` a ring pin in the casing, a firing pin spring, a pair of levers for holding the ring pin in retracted position, a rotor having a detonator, a startercontrol rod engageable with the clockwork movement, the inner end of the rod including a segment for holding the rotor and one oi' the tiring pin holding levers, means whereby the starter rod is held against rotation until it has lbeen displaced' longitudinally on impact, means releasable on launching of the bomb for holding the starter rod against rotational longitudinal displacement, a rod having a segment on one end engageable with the other firing pin holding lever, and a lever on said rod engaging the segment of the timing lever.

4. In a fuse for bombs, a casing, a clockwork movement in the casing including a timing lever, a ring pin in the casing, a firing pin spring, a pair o! levers for holding the ring pin in retracted position, a member carrying a detonator and movable to -position the detonator in line with -the firing pin, a rotatable starter control rod engageable with the clockwork movement, said rod adapted when restrained against rotation to hold the detonator member and one oi the firing pin holding levers and adapted when rotated to control release of said member and lever, means whereby the starter control rod is held against rotation until it has been displaced longitudinally on impact, means releasable upon launching of the bomb for holding the starter control rod against rotational and longitudinal displacement, and a connection between the timing lever and the other firing pin holding lever whereby the timing lever is under the inuence of the ring pin spring.

5. In afuse for bombs, a casing, a clockwork movement inthe casing, a firing pin in the casing, a ring pin spring, a pair of levers for holding the ring pin in retracted position, a rotatable starter control rod engageable with the clockwork movement and with one of the ring pin holding levers, said rod adapted when restrained against rotation to hold the clockwork movement and the lever and adapted when rotated by the clockwork movement -to control timed release of said lever, means whereby the starter control rod is held against rotation until it has been displaced longitudinally on impact, means releasable upon launching of the bomb for holding the starter control rod against rotational and longitudinal displacement and means operable after time-set running of the clockwork mechanism for controlling release of the other ilring pin holding lever.

6. In a fuse for bombs, a casing, a clockwork y starter control rod engageable with thek clockworkmovement and with one of the firing pin holding levers, said rod adapted when restrained against rotation to hold the clockwork movement and the lever and adapted when rotated by the clockwork movement to control time release of said lever, means whereby the starter control rod is held against rotation until it has been displaced longitudinally on impact, and means operable after time-set running of the clockwork mechanism for controlling release oi the other firing pin holding lever.

7. In a fuse for bombs, a casing, a clockwork movement in the casing, a iiring pin in the casing, a ilring pin spring, a pair of levers for-holding the iiring pin in retracted position. means operable after a fixed minimum time of running of the clockwork movement for releasing one of the levers, and means operable af-ter time-set running of the clockwork'movement for releasing the other lever. y

8. In a fuse for bombs, a casing, a clockwork movement in the casing, a ring pin in the cas1ng, v a ilring pin spring. a pair of'leversfor holdingl the ring pin'in retracted position, amember controlling starting of the clockwork movement and driven thereby to control -timed of; one lever and means operable after'time-setj running of the clockwork movement ior releasing Y the other lever.

9. In a fuse for bombs, a casing including a tracted position, a member carrying a detonatox and movable -to position the detonator in line with the ring pin, a rotatable starter control rod having a segment for holding the detonator member and the lever, a 'gear on said rod meshing with the clockwork movement, means whereby the rod is held against rotation until it has been displaced longitudinally on impact, a ilrst plunger for holding the rod against movement, a spring acting to withdraw the plunger, a second plunger for holding the rst plunger in engagement with the rod, a spring acting -to remove the second plunger, an arming bolt released on launching of the bomb and holding the second plunger in position to oppose movement of the iirst plunger, and a bolt .controlled by the second plunger and movable to lock the cover to the casing.

10. In a fuse for bombs, a casing, a clockwork movement in the casing, a tiring pin in the casing, a firing pin` spring, a lever for holding the firing pin in retracted position, a member carrying a detonator and movable to position the detonator in line with the ring pin, a rotatable starter control rod having a segment for holding the detonator member and the lever, a gear on said rod meshing with the clockwork movement, means whereby the rod is held against rotation until it has been displaced longitudinally on impact, a iirst plunger for holding the rod against movement, a spring acting to withdraw the plunger, a second plunger for holding the iirst plunger in engagement with the rod, a spring acting to remove the second plunger, an arming bolt released on launching of the bomb and holding the second plunger in position to oppose movement of the iirst plunger.

1l. In a fuse, a casing, a clockwork movement in the casing, a rotatable starter controlv rod having a gear meshing with the clockwork movement, a member whose movement is controlled by rotation of the starter rod, means whereby the plunger, a member holding til it has been `displaced longitudinally on impact, a nrst plunger forv holding the rod against movement, a spring acting to withdraw the plunger. a second plunger rod is held against rotation for holding the first plunger in engagement with l the rod, a spring acting to remove the second plunger and an arming bolt released at the commencement of night and holding the second plunger in position to oppose movement o! the rst plunger.

l2. In a fuse, a casing, a clockwork movement in the casing, a rotatable starter control rod having agear meshing with the clockwork movement. a member whose movement is controlled by rotation ot the starter rod, means whereby the rod is held against rotation until it has been displaced longitudinally on impact, and means releasable on launching of the bomb for holding the starter rod against movement.

13. In a ipse, a casing, a removable cover for the casing, 'aclockwork movement in the casing and including controlmember, a holding member opposingmovement of the starting member, .a vplunger-opposing movement of the holdingv member, means operable at the commencement oi' flight for controlling movement `of they plunger to release the holding member, and a bolt controlled" bythe plunger and movable vto lock the cover to the casing.

14,.. In a bomb, 'a body, a fuse casing ing, a pawl carried by the casing a s pring actin to move the pawl into engagementl with the boing $0 y threaded on the bomb body. a removable cover for the cas'- body, a movable control member in the casing, a 8B pair oi plungers in the casing. a spring i'or each bothplungers against the action of .their springs whereby one plunger restrains the pawl and the other plunger restrains the control member, means operable at the commencement of iiight for controlling release of the plungers, and one of the plungers movable to engaie alnd locbltlhe cover to the casing.

n a b, a body, a fus on the bomb body' e casing threaded spring acting to move the pawl into en i gagement withl the bomb body, a plunger for holding the pawl clear of the bomb body, a spring acting to removev the plunger from holding engagement with the pawl and means a pawl carried by the casing, a 4g Operable at the com- 50 mencement of iiight for controllin l plunger. g re ease of the 16. In a fuse, a casing, a removablecover ior the casing, a movable member in the casing, a

bolt in the casing, and having one end normally 55 17. In a bomb, a body. a fuse casing threaded on the bomb body, a removable cover for the casing. means carried by the casing for locking it to g5 the bomb body, and arranged for manual release when the cover is removed,and means operable at the commencement of iiight for locking the cover to the casing.

18. In a fuse, a casing. a clockwork movement 70 inthe casing and including a timing lever having a segment, a tiring pin in the casing, a firing pin spring, a lever for holding the ring pin in retracted position, a 'rod having a'segment on one end for restraining the firing pin holding lever, 75

and a lever on said rod engaging the segment oi' the timing lever.

19. In a. fuse, a casing, a removable cover for the casing, a clockwork movement in the casing, a

setting disk driven by the clockwork movement and having a. peripheral recess, a lug on the disk, a. timing lever adapted tn ride on the periphery of the disk and enter the recess, a stop member, a 

